Cycloolefin-based polymer and process for producing the same

Details Cycloolefin-based polymer and process for producing the same Cycloolefin-based polymer and process for producing the same

1997-08-20

2001-08-21

Lipman, Bernard (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

C528S482000, C528S50200C

Reexamination Certificate

active

06277923

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a cycloolefin-based polymer with a very low content of foreign matters and to a molded article obtained by using the cycloolefin-based polymer. The invention also relates to a process for producing a cycloolefin-based polymer with a very low content of foreign matters.
An integrated circuit (IC) is an electronic circuit provided with a large number of transistors, resistances, capacitors, etc. on the surface of a silicon wafer several millimeters square. With recent increasing requirement for electronic instruments of more enhanced performance and smaller size, the degree of integration of the IC is becoming increasingly high, and the IC is developing through LSI to super LSI and VLSI (ultra LSI). In the LSI and super LSI, the necessary circuits are formed by printing the circuits on a silicon wafer by using a photosensitive resist or the like, and then successively applying the treatments of surface oxidation, etching by chemicals, doping, vapor deposition, supersonic cleaning, etc. With the increasingly high degree of integration of the IC, the width of the circuit is decreasing to as small as the order of submicron. Consequently, when impurities, particularly minute particles, are present on the silicon wafer surface, they will adversely influence on the withstand voltage characteristic of the oxide film of the LSI, and the extent of the influence is increasingly large as the degree of integration increases. Therefore, for example, an ultrapure water having a very low content of minute particulate foreign matters is used in the cleaning step.
However, the etching treatment with chemicals and the cleaning with ultrapure water, which are commonly conducted by placing the silicon wafer in a plastic case called a carrier and immersing it in an etching liquid or ultrapure water, have a problem in that minute particulate matters are generated from the carrier itself. Thus, these plastic cases have hitherto been made by using fluoresins, such as PFA, polypro-pylene or like resins, which are excellent in chemical resistance, but these resins have shortcomings in that they are apt to generate minute particulate foreign matters on contacting with the silicon wafer owing to their low surface hardness and that they do not give satisfactory dimensional accuracy and surface smoothness at the time of molding.
As a means for solving such problems, JP-A-7-126434 discloses a treating vessel for use in semiconductor production steps which uses a thermoplastic norbornene type resin. However, the vessel also shows the generation of minute particulate foreign matters at the time of ultrasonic cleaning, etc. and hence cannot be deemed fully satisfactory.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a cycloolefin polymer with a very low content of foreign matters, a molded article obtained by using the cycloolefin-based polymer and a process for producing the cycloolefin-based polymer.
After extensive study for overcoming the problems of the prior art, the present inventors have found that a plastic case for a carrier which generates very little foreign matters even when used for chemical treatment and ultrasonic cleaning by using a cyclo-olefin-based polymer in which the content of foreign matters having a particle diameter of 0.5 &mgr;m or more has been reduced. Moreover, when the cycloolefin-based polymer used to prepare various molded articles by injection molding or other means, molded articles which are excellent in dimensional stability and dimensional accuracy and have a very smooth surface can be obtained. Accordingly, the use of the resin can be extended to those fields where a particularly high degree of surface smoothness is required. Such cycloolefin-based polymers with a very low content of minute foreign matters can be easily obtained, for example, by filtering the polymer in the state of solution through a filter which has a capturing function based on electric charges.
In the present invention, the “foreign matters” refer to impurities (contaminants), catalyst residues, gels and like substances which have got mingled in the polymer as minute particulate substances, fibrous substances, etc. without becoming compatible with the cycloolefin-containing polymer. The content of foreign matters having a particle diameter of 0.5 &mgr;m or more refers to the value determined with a 1.5% by weight toluene solution of the polymer by using a microparticle detector by light scattering method.
The present invention has been accomplished on the basis of these findings.
According to the present invention, there are provided:
a cycloolefin-based polymer which has a repeating unit represented by the formula (1) or the formula (2)
 wherein
R
1
-R
4
each independently represent a hydrogen atom, hydrocarbon group, halogen atom, hydroxy group, ester group, alkoxy group, cyano group, amido group, imido group or silyl group, or a hydrocarbon group substituted with a polar group (that is, halogen atom, hydroxy group, ester group, alkoxy group, cyano group, amido group, imido group or silyl group), provided that two or more of R
1
-R
4
may combine with each other to form an unsaturated bond, single ring or multi-ring, the single ring or the multi-ring may have a double bond or may form an aromatic ring, and R
1
conjointly with R
2
or R
3
conjointly with R
4
may form an alkylidene group;
R
5
and R
6
each independently represent a hydrogen atom, alkyl group or aryl group;
the symbol
- - -
represents a carbon-carbon single bond or double bond; and
n and m are numbers specified by the mathematical expressions n+m=1, n=0.2-1 and m=0-0.8;
has an intrinsic viscosity [&eegr;] of 0.01-20 dl/g as determined in decalin at 80° C. and has a content of foreign matters having a particle diameter of 0.5 &mgr;m or more of 3×10
4
particles/g or less,
a process for producing a cycloolefin-based polymer having an intrinsic viscosity [&eegr;] of 0.01-20 dl/g as determined in decalin at 80° C. and a content of foreign matters having a particle diameter of 0.5 &mgr;m or more of 3×10
4
particles/g or less which comprises the step of filtering an organic solvent solution of a cycloolefin-based polymer having a repeating unit represented by the formula (1) or formula (2) through a filter which has a capturing function based on electric charges,
a molding material which comprises a cycloolefin-based polymer having a repeating unit represented by the formula (1) or the formula (2), the cycloolefin-based polymer having an intrinsic viscosity [&eegr;] of 0.01-20 dl/g as determined in decalin at 80° C. and a content of foreign matters having a particle diameter of 0.5 &mgr;m or more of 3×10
4
particles/g or less, and
a molded article obtained by molding the molding material.
DETAILED DESCRIPTION OF THE INVENTION
Cycloolefin-Based Polymer
The cycloolefin-based polymer of the present invention is a polymer which has a repeating unit represented by the formula (1) or the formula (2)
wherein
R
1
-R
4
each independently represent a hydrogen atom, hydrocarbon group, halogen atom, hydroxy group, ester group, alkoxy group, cyano group, amido group, imido group or silyl group, or a hydrocarbon group substituted with a polar group (that is, halogen atom, hydroxy group, ester group, alkoxy group, cyano group, amido group, imido group or silyl group), provided that two or more of R
1
-R
4
may combine with each other to form an unsaturated bond, single ring or multi-ring, the single ring or the multi-ring may have a double bond or may form an aromatic ring, and R
1
conjointly with R
2
or R
3
conjointly with R
4
may form an alkylidene group;
R
5
and R
6
each independently represent a hydrogen atom, alkyl group or aryl group;
the symbol
- - -
represents a carbon-carbon single bond or double bond; and
n and m are numbers specified by the mathematical expressions n+m=1, n=0.2-1 and m=0-0.8.
A preferred example of the cycloolefin-based

Affiliated with

Also associated with

Rating

Cycloolefin-based polymer and process for producing the same does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Cycloolefin-based polymer and process for producing the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cycloolefin-based polymer and process for producing the same will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2465836